Sedimentary Rock (Technically A Microcrystalline Quartz Mineral Aggregate)

River Stone / Pebble

Clastic Sediment (composed largely of Quartz, Feldspar, and various rock fragments)

Red Brecciated Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Ferruginous Sandstone

Sandstone, Iron-rich

Ferruginous Sandstone

Arenite with Iron-Oxide Cement (FeO(OH)·nH2O / Fe2O3)

Red Sandstone Pebble

Arenite (primarily Quartz SiO2 with Hematite Fe2O3 staining)

Agate

Silicon dioxide (SiO2)

Milky Quartz

Milky Quartz (Silicon Dioxide, SiO2)

Quartzite (River Cobble)

SiO2 (Quartz-rich Metamorphic Rock)

Yellow Jasper

Silicon Dioxide (SiO2) with hydrated iron oxide impurities (Goethite)

Chert with Quartz/Calcite Vein

Microcrystalline Silica (SiO2)

Quartz (Microcrystalline variety)

Silicon Dioxide (SiO2)

Sandstone Beach Pebble

Clastic Sandstone (SiO2 - Quartz-dominant)

Quartz (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Chert (with Limestone and Iron Oxide staining)

Cryptocrystalline Quartz (SiO2)

Basalt-Amugydule (Amygdaloidal Basalt)

Aphanitic Mafic Igneous Rock with Vesicle Infillings

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Conglomerate

Conglomerate (clastic sedimentary rock)

Quartz

Silicon dioxide (SiO2)

Lapis Lazuli

Lapis Lazuli (A complex rock primarily composed of Lazurite: (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Lapis Lazuli

Lapis Lazuli (Mineral composition: Lazurite (Na,Ca)8(AlSiO4)6(SO4,S,Cl,OH)2, Calcite, and Pyrite)

Yellow Jasper

Silicon Dioxide (SiO2) with Goethite or Iron Oxide inclusions

Limestone

Calcium Carbonate (CaCO3)

Quartzite / Sandstone / Chert Mix

Silicon Dioxide (SiO2)

Satin Spar (often marketed as Selenite)

Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

Conglomerate

Conglomerate (Sedimentary rock)

Chert (specifically Flint)

Microcrystalline Quartz (SiO2)

Picture Jasper

Silicon dioxide (SiO2)

Chert / Flint Nodules in Limestone

Silicon Dioxide (SiO2) within Calcium Carbonate (CaCO3)

Chert (Common Opal variant)

Microcrystalline Quartz (SiO2)

Druzy Quartz on Agate/Chert

Silicon Dioxide (SiO2)

River Cobble (likely Basalt or Chert)

Siliceous River Rock / Microcrystalline Quartz / Mafic Igneous

Red Jasper (possibly Carnelian)

Silicon Dioxide with Iron Oxide inclusions (SiO2 + Fe2O3)

Gneiss

Gneiss (High-grade regional metamorphic rock)

Granite

Granite (a broadly defined plutonic igneous rock, often more specifically classified as quartz monzonite or granodiorite based on precise mineral percentages)

Conglomerate

Clastic sedimentary rock (Puddingstone)

Milky Quartz with Country Rock contact

Silicon Dioxide (SiO2) in contact with Metamorphic/Igneous rock

Chert (Flint)

Microcrystalline Quartz (SiO2)

Quartz Vein in Host Rock (Gabbro or Basalt)

Silicon Dioxide (SiO2) with Mafic Silicates

Yellow Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Banded Agate

Chalcedony / Silicon Dioxide (SiO2)

Chert (often colloquially called Flint)

Chert (Microcrystalline Quartz, SiO2)

Chert (Chert Pebble)

Microcrystalline or cryptocrystalline Quartz (SiO2)